1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a compensation layer formed on an inner surface of a substrate and a method of manufacturing the same.
2. Discussion of the Related Art
With the development of modern information and communication technologies, liquid crystal display (LCD) devices having high brightness, large-sized screens, low power consumption and low price are in demand.
The LCD device includes first and second substrates having first and second electrodes, respectively that are attached such that the first electrode faces the second electrode, and a liquid crystal layer interposed between the first and second substrates. The LCD device displays an image using light transmittance that is changed when liquid crystal molecules are moved by an electric field generated by applying a voltage between the first and second electrodes.
Because the liquid crystal is optically an anisotropic material having an ordinary refractive index and an extra-ordinary refractive index, it has characteristics where the light path and birefringence vary depending on an incident angle of light. When the light emitted from a backlight is linearly polarized through a lower polarizing film of a liquid crystal panel and then passes through the liquid crystal having the optical anisotropy in a direction (case I) perpendicular to the liquid crystal cell and at a predetermined angle (case II) with respect to the liquid crystal cell, retardation values in cases I and II are different, and thus a phase difference is generated. As a result, the characteristics of light passing through the liquid crystal in the cases I and II are different according to the viewing angle.
Therefore, the related art LCD device has a low visibility due to a variation of contrast ratio and gray scale inversion, that are characteristics determining how clearly an image is seen.
The above problem can be overcome by compensating the optical phase difference generated in the liquid crystal cell, thereby enhancing the viewing angle. Therefore, a compensation film that can compensate for the optical phase difference is attached on a substrate to enhance the viewing angle.
However, when the compensation film is attached on the substrate, foreign particles may adhere to the compensation film. Also, the attached compensation film limits reducing the thickness of the liquid crystal panel. To solve these problems, there has been research into a compensation layer for compensating the optical phase difference formed on an inner surface of the substrate to thereby prevent foreign particles from adhering and decreasing the thickness of the liquid crystal panel.
The compensation layer is formed on the entire inner surface of the substrate, and a column spacer for maintaining a cell gap between two substrates is formed on the compensation layer. Because the compensation layer is formed of a weak material with a weak restoring force, any pressure applied to the LCD device causes the column spacer to compress the compensation layer. Thereafter, when the pressure is released, the compensation layer does not return to its original state and thickness due to its weak restoring force. Therefore, the cell gap between two substrates decreases, which may result in a blemish.
Also, because the compensation layer is formed on the entire inner surface of the substrate, a seal pattern disposed along edges of the LCD device is formed on the compensation layer. However, because an adhesive force between the compensation layer and the seal pattern is very weak, a defect, such as a seal pattern burst may occur.